A Baystate spokesman said Stewart remained in the intensive care unit Monday.

Bouchard said investigators believe a sports utility vehicle or pickup truck struck Stewart because of the nature of his injuries and material from the vehicle found at the scene. The vehicle would have sustained damage to its right side, he said, and police are asking local body shops to alert authorities if such a vehicle is taken in for repairs.

"It is without a doubt a motor vehicle accident," Bouchard said. "We have not been able to identify that vehicle or the person that operated that vehicle."

"We would urge the person who was involved in this to contact us as soon as possible so that we can put this matter to rest. It would be in their best interest to contact police and tell us what happened," Bouchard said.

Anyone with information is asked to call Officer William Ludemann at 860-763-8919.